Search

A traditional electrochromic device contains at least five functional layers; the electrochromic film exactly faces the counter electrode and matches it in size and color. This face-to-face structure is cumbersome for device flexibility and integration; thus, it is difficult for these devices to meet sophisticated application needs. Concurrently, a lateral electrochromic structure in which the electrochromic film and the counter electrode are arranged in a shoulder-by-shoulder manner was proved to be a superior choice for many specific applications. However, systematic exploration of the shoulder-by-shoulder EC structure is lacking. Herein, a WO3vs. WO3 electrochromic system was constructed to systematically discuss the EC characteristics and superior applications of the shoulder-by-shoulder structure. Surprisingly, when one EC unit in the shoulder-by-shoulder system was first colored at a certain transmittance, a much faster response time and a lower driving voltage than those of the traditional face-to-face structure were achieved. Additionally, this configuration endowed the counter electrode with great freedom in terms of material, shape and placement position, and it showed great superiority in vast applications. These results provide insight into the structure evolution of electrochromic devices.

A novel three-dimensional ball-flower-like g-C3N4/NiO (GN) photocatalyst was firstly fabricated by a simple two-step calcination method for enhanced degradation capability. Our investigation focuses on the construction of p–n heterojunction and specific ball-flower-like structure to overcome limitations of single-component semiconductors, such as low surface area, poor light response and fast recombination of the photogenerated electrons and holes. Detailed photocatalytic experiments revealed that the novel ball-flower-like GN (50%) exhibited much higher activity for the removal of TC and Cr6+ than single g-C3N4, NiO and traditional layered GN. The trapping experiments proved that the superoxide radicals ( $$ ^{ \cdot } {\text{O}}_{2}^{ - } $$ ), holes (h+) and electrons (e−)were the main active species in the photodegradation process. Moreover, three different degradation pathways and fourteen intermediate products of TC were also determined by the LC/MS analysis and these intermediates could be further degraded completely into CO2, H2O, $$ {\text{NH}}_{4}^{ + } $$ , carboxylic acids and any other inorganic intermediates. These results will benefit the fabrication of other 3D p–n heterojunction photocatalysts and their potential application in treatment of organic pollutants.

In this work, W18O49/WOx/W dendritic nanostructures were facilely fabricated by a one-step thermal evaporation method, into which a reduction process at a temperature as high as 1250 °C was deliberately inserted. In the dendritic nanostructure, W18O49 nanowires acted as tree trunks, W nanoparticles acted as fruits grown on the tree trunks and amorphous WOx layers acted as self-assembly bonds between them. In the reduction process, dangling bonds and defects were expected in this integrated nanostructure, greatly enhancing its optical absorption covering the full spectrum (200–2500 nm). High-performance degradation of methyl orange using these dendritic nanostructures under vis-NIR irradiation (with wavelength ≥550 nm) was achieved for the first time, with good cycling durability in view of no deterioration after ten reaction cycles, which stemmed from their enhanced optical absorption and boosted the separation of photoexcited carriers distinctively by the interfacial tunneling effect of electrons owing to the existence of the two-dimensional WOx bond layer (1–2 nm). This dendritic nanostructure holds great promise for waste-water treatment and organic dye degradation.

The macro- and micro-physical properties of cement-stabilized steel slag (CSS) base materials in a highway project were studied. A discrete element model of CSS with a real steel slag shape was constructed using Particle Flow Code 3D and 3D scanning technology. The sensitivity between the macro- and micro-parameters of the sample was explored, and a nonlinear regression equation was established to analyze the relationship between these parameters. Uniaxial compression simulation tests were conducted on CSS with steel slag contents of 0%, 10%, 30%, and 50%. By combining contact calculation, crack location, energy tracking, acoustic emission (AE) monitoring, and other program systems, the macro- and micro-mechanical properties and micro-crack evolution law of the samples in the failure process were analyzed in terms of strength, energy, and fracture damage. The damage mechanism of CSS was also revealed. Results showed that with the increase in steel slag content, the elastic modulus and peak stress of the samples increased, the Poisson’s ratio decreased, and the post-peak stress curve steepened, indicating obvious brittle failure characteristics. With the increase in steel slag content, the crack initiation stress, thickness of the fracture surface, and number of internal micro-cracks in CSS increased exponentially. In the uniaxial compression test, AE intensity underwent five stages, in which the peak moment of AE intensity exhibited hysteresis compared with the moment of the peak stress. Absorption and release phenomena of strain energy were observed in the process of specimen failure. When the steel slag content increased, the total strain energy absorbed by the specimen increased. When the absorbed energy exceeded the bond strength, the bond ruptured with the release of energy. The main crack of the sample penetrated and stretched to the direction of strain energy release to form a macroscopic fracture surface.

Rechargeable lithium batteries are the most practical and widely used power sources for portable and mobile devices in modern society. Manipulation of the electronic and ionic charge transport and accumulation in solid materials has always been crucial for rechargeable lithium batteries. The transport and accumulation of lithium ions in electrode materials, which is a diffusion process, is determined by the concentration distribution of lithium ions and the intrinsic structure of the electrode material and thus far has not been manipulated by an external force. Here, we report the realization of controllable two-dimensional movement and redistribution of lithium ions in metal oxides. This achievement is one kind of centimeter-scale control and is achieved by a magnetic field based on the ‘current-driving model’. This work provides additional insight for building safe and high-capacity rechargeable lithium batteries., Ion transport properties are critical to some emerging technologies. Here, the authors show the controllable 2D movement and redistribution of Li-ions in metal oxides such as WO3 by a magnetic field. The success is based on a current-driving model which also works for other cations including H+, Na+, Zn2+ and Ca2+.

Owing to the accumulation of trapped ions in host structures, electrochromic devices (ECDs) suffer from diminished optical modulation and reduced device efficiency under long-term charge insertions and extractions. The accumulation of trapped ions also results in structural changes and mechanical degradation of the electrochromic film, for which very few studies are currently on hand. Here, we report on an explorative study about the mechanical degradation for a WO3-based monolithic ECD: glass/ITO/WO3/LiClO4(PEO)/TiO2/ITO/glass. For the WO3 EC film, both the electrochemical degradation from cyclic voltammetry and the volume expansion by in-situ AFM monitoring were studied. Under the collective effects of these two aspects, the mechanical degradation process of the ECD was recorded through surface morphology evolutions of the WO3 film during life cycling of the ECD to its final failure for up to 90 000 cycles. The surface morphology of the WO3 film underwent three stages: (I) it first became increasingly denser and denser when the cycles were low, approximately 10 000 times; (II) when the cycles went up to 30 000 times or more, the surface of the WO3 film had an uneven distribution, with some dense islands surrounded by loose areas; and (III) when the cycling continued, this situation got worse, and finally, the WO3 film started to crack. This exploration provides new insights into the degradation mechanism of WO3-based ECDs upon repetitive insertions and extractions of Li ions in practical use.